This invention relates to a touch panel input apparatus in which a display unit such as a CRT display or liquid crystal display is combined with a transparent touch panel superposed on the display screen of the display unit.
Such a touch panel display apparatus is known from the disclosure of, for example, JP-A-60-124724. In the prior art touch panel input apparatus, effective key-input ranges on the touch panel have been fixed for individual input keys. Therefore, individual patterns to be displayed on the display screen of the display unit to indicate the individual key input positions are required to be arranged and shaped to conform to the positions of the individual keys on the touch panel, respectively. Because of such a requirement, the prior art touch panel input apparatus has been disadvantageous in that the arrangement and shape of the patterns indicating the key input positions on the touch panel have been inevitably limited from the aspect of design.